What are canal rays and why they are called canal rays?

Canal rays, also known as positive rays, are streams of positively charged particles, typically ions or atoms, that are emitted from the anode during gas discharge in a cathode ray tube. They are called "canal rays" because they travel through narrow channels or "canals" formed in the gas, which is ionized by the electrons emitted from the cathode. The discovery of canal rays helped in understanding the nature of atomic structure and led to the identification of different elements based on their positive ion emissions.